1. Field of the Invention
The present invention relates to golf clubs, and in particular, relates to a golf club of which characteristics such as a lie angle, a slice angle, and a progression can be easily adjusted. In addition, the present invention relates to methods for adjusting the characteristics of the golf club.
2. Description of the Related Art
A golf club includes a shaft, and a head attached to a top end portion of the shaft. A grip is attached to a base end portion of the shaft.
A conventional general golf club head includes a hosel hole that is directly provided to the head, and a shaft is inserted into and bonded to the hosel hole with an adhesive agent. An epoxide-based adhesive agent is generally used for the adhesive agent. In making a shaft change, the hosel portion is heated to destroy the structure made from the cured epoxy resin, and thereby the shaft can be pulled out of the hosel hole.
The conventional general golf club head having this configuration has a lot of trouble in making a shaft change. In addition, characteristics such as a lie angle, a slice angle, and a progression of the golf club head cannot be adjusted.
JP-A-2012-165864 describes a golf club that allows a shaft change to be easily made, and of which characteristics such as a lie angle, a slice angle, and a progression can be adjusted, and describes a method for adjusting the characteristics of the golf club. The golf club head of JP-A-2012-165864 has a configuration such that a shaft case having an approximately cylindrical shape is bonded to the top end of a shaft, the shaft case is inserted into a cylinder portion of a hosel, a divider is provided to a lower portion of the cylinder portion, a spacer is provided between the top end of the shaft case and the divider, the shaft case is engaged in the spacer so as not to be rotatable, a stopper member arranged to prevent the spacer from rotating is provided between the spacer and the divider, and a bolt that is inserted into a bolt through hole provided to the divider and a bolt through hole provided to the spacer from a sole side of the head is screwed into the shaft case, and thereby the shaft case is fixed to the head.
In the golf club of JP-A-2012-165864, loosening and unbolting the bolt allows the shaft case to be pulled out of the cylinder portion of the hosel. Thus, for example, when a shaft case having a configuration such that the axis center of the shaft is inclined in a slanting direction (e.g., an oblique direction) with respect to the axis center of an insert hole of the shaft case is used, changing the phase of a circumferential direction of the shaft case changes an attaching direction of the shaft with respect to a head main body, and thereby a lie angle and a slice angle are changed.
In addition, when a shaft case having a configuration such that the axis center of the shaft is inclined in a slanting direction (e.g., an oblique direction) with respect to the axis center of an insert hole of the shaft case is used, changing the phase of a circumferential direction of the shaft case changes an attaching direction of the shaft with respect to a head main body, and thereby a lie angle and a slice angle are changed.
Thus, only the lie angle and the slice angle can be adjusted in the golf club having the identical shaft and the identical head main body.
In addition, when a shaft case having a shape such that an axis center position of an insert hole of the shaft case is displaced in a parallel translation manner from an axis center position of an insert hole of a hosel is used, changing the phase of a circumferential direction of the shaft case allows a progression and the distance between a shaft and the center of gravity (the center of gravity distance) to be adjusted in the golf club having the identical shaft and the identical head main body.
In JP-A-2012-165864, a shaft case of a pattern identical to the shaft case is prepared as a shaft case, and a shaft with other characteristics is bonded to the prepared shaft case to prepare a shaft case-shaft connected body, and by replacing the previously-used shaft case-shaft connected body with the prepared shaft case-shaft connected body to attach to the hosel of the head, the golf club having the different shaft can be obtained.
In the golf club of JP-A-2012-165864 described above, an insertion depth of the shaft case into a hosel column cannot be changed.